A Comparison of the X-Ray Diffraction and Nitrogen Adsorption Surface Areas of Carbon Blacks and Charcoals

Abstract

The surface areas, as determined from X-ray diffraction and low temperature nitrogen adsorption data, were compared for a number of carbon blacks and activated charcoals. Comparative data were also obtained on samples of charcoal at various stages of activation and after calcination. The X-ray diffraction data indicated that all the samples examined were composed of small graphitelike crystallites of the same order of magnitude, which had specific surfaces of about 2500 to 3000 sq. m. per cc. The nitrogen adsorption surface of a highly activated charcoal was found to be about equal to the X-ray surface. It is suggested that the crystallite surface represents the potential adsorption surface of a carbonaceous material and, providing that crystal growth does not occur during activation, the activation process makes these surfaces available to external adsorbate.

Fundamentals and Practical Implications of Activated Carbon Production by Partial Gasification of Carbonaceous Materials

“…alkali metals (15) and fluorine (16) with activated carbon. The interlayer spacing in activated carbons, however, is considerably higher than in the case of graphite (3.44-3.65 ~) (17). The second type of structure, Riley describes as a disordered, cross-linked space lattice of the carbon hexagons, which results from their deflection from the planes of graphitic layers.…”

The Specific Surface Areas of Montmorillonites

“…Hence surface areas calculated from average crystal sizes should be comparable with gas adsorption values if all crevices between crystals are accessible to the adsorbed gas. Often this condition is not fulfilled (Arnell & Barss, 1948;Nielsen & Bohlboro, 1952) and this is particularly so with crystals that are thin laminae prone to mutual orientation, such as the clay minerals. Surfaces that are measured in montmorillonite will be shown to be external to aggregates of crystals; it is necessary to increase the porosity of aggregates by, for example, dilution with kaolinite to obtain specific surface areas comparable to those deduced from measurements of crystal sizes.…”

The Differential Thermal Analysis of Perchlorates. II. The System LiClO4–LiNO3

“…Anhydrous lithium perchlorate was prepared by neutralization of a solution of lithium hydroxide monohydrate with aqueous perchloric acid followed by prolonged drying of the resulting solution in an oven at 250°, and then final vacuum (1)(2)(3) mm.) dehydration of the solid for 8 hours at 160°.…”